LM4930
LM4930 Audio Subsystem with Stereo Headphone & Mono Speaker Amplifiers
Literature Number: SNAS212B
LM4930
Audio Subsystem with Stereo Headphone & Mono
Speaker Amplifiers
General Description
The LM4930 is an integrated audio subsystem that supports
voice and digital audio functions. The LM4930 includes a
high quality I
2
S input stereo DAC, a voice band codec, a
stereo headphone amplifier and a high-power mono speaker
amplifier. It is primarily designed for demanding applications
in mobile phones and other portable devices.
The LM4930 features an I
2
S serial interface for full range
audio, a 16-bit PCM bi-directional serial interface for the
voice band codec and an two-wire interface for control. The
full range music path features an SNR of 86dB with a 16-bit
48kHz input. The stereo DAC can also be used while the
voice codec is in use. The headphone amplifier delivers
25mW
RMS
toa32Ωsingle-ended stereo load with less than
0.5% distortion (THD+N) when AV
DD
= 3V. The mono
speaker amplifier delivers up to 330mW into an 8Ωload with
less than 1% distortion when AV
DD
=3V.
The LM4930 employs advanced techniques to reduce power
consumption, to reduce controller overhead and to eliminate
click and pop. Boomer audio power amplifiers were de-
signed specifically to provide high quality output power with
a minimal amount of external components. It is, therefore,
ideally suited for mobile phone and other low voltage appli-
cations where minimal power consumption is a primary re-
quirement.
Key Specifications
jP
LS OUT
at AV
DD
= 5.0V, 8Ω
1% THD+N 1W (typ)
jP
LS OUT
at AV
DD
= 3.0V, 8Ω
1% THD+N 330mW (typ)
jP
H/P OUT
at AV
DD
= 3.0V, 32Ω
0.5% THD+N 25mW (typ)
jSupply voltage range
DV
DD
(Note 8) 2.6V to 4.5V
AV
DD
(Note 8) 2.6V to 5.5V
jTotal shutdown current 2µA (typ)
jPSRR at 217Hz, AV
DD
= 3V 50dB (typ)
Features
n16-bit resolution 48kHz stereo DAC
n16-bit resolution 8kHz voice codec
nI
2
S digital audio data serial interface
nTwo-wire serial control interface
nPCM voice audio data serial interface
n25mW/channel stereo headphone amplifier
n330mW mono 8Ωamplifier (at AV
DD
= 3.0V)
n32-step volume control for audio output amplifiers
nNo snubber networks or bootstrap capacitors are
required by the headphone or hands-free amplifiers
nDigital sidetone generation with adjustable attenuation
nGain controllable headphone amp, mono BTL amp, mic
preamp
nAvailable in the 36–bump micro SMD and 44–lead LLP
packages
Applications
nMobile Phones
nMobile/low power audio appliances
nPDAs
Boomer®is a registered trademark of National Semiconductor Corporation.
September 2004
LM4930 Audio Subsystem with Stereo Headphone & Mono Speaker Amplifiers
© 2004 National Semiconductor Corporation DS200720 www.national.com
Typical Application
20072003
FIGURE 1. Typical I
2
S + Voice codec application circuit for mobile phones
LM4930
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Connection Diagrams
36-Bump micro SMD micro SMD Marking
20072002
Top View
Order Number LM4930ITL
See NS Package Number MKT - TLA36KRA
20072056
Top View
X - Date Code
T - Die Traceability
G - Boomer Family
B6 - LM4930ITL
44 – Lead LLP 44 – Lead LLP Marking
20072086
Top View
Order Number LM4930LQ
See NS Package Number MKT - LQA44A
20072087
Top View
N - National Logo
U - Wafer Fab Code
Z - Assembly Plant Code
XY - Two Digit Date Code
TT - Die Run Code
L4930LQ - LM4930LQ
LM4930
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Pin Descriptions
A1 MIC_P Microphone positive differential input
A2 MIC_N Microphone negative differential input
A3 AVDD_MIC Analog V
dd
for microphone preamp
A4 DAC_REF D/A converter reference voltage
A5 SDA Two-wire control interface serial data pin
A6 SCL Two-wire control interface serial clock pin
B1 AGND_MIC Analog ground for microphone preamp
B2 MIC_BIAS Microphone bias supply output (2V)
B3 MIC_REF Internal fixed-reference bypass capacitor decoupling pin
B4 ADDR Control bus address select pin
B5 PCM_SDI PCM serial data in
B6 PCM_CLK PCM Serial clock pin
C1 AVDD_HP Analog V
dd
for headphone amplifier
C2 NC No Connect
C3 BYPASS Half-supply bypass capacitor decoupling pin
C4 PCM_SYNC PCM Frame sync pin
C5 I2S_DATA I
2
S serial data input
C6 DGND_D Digital ground
D1 HP_L Headphone amplifier connection (Left)
D2 HP_R Headphone amplifier connection (Right)
D3 HPSENSE_IN Connection for sense pin of headphone jack
D4 PCM_SDO PCM serial data out
D5 I2S_CLK I
2
S serial bit clock
D6 DVDD_D Digital V
dd
E1 AGND_HP Analog ground for headphone amplifier
E2 LS- Loudspeaker amplifier BTL negative out (-)
E3 HPSENSE_OUT Logic output pin to indicate headphone connection status. Outputs logic high when
HPSENSE_IN is high and outputs logic low when HPSENSE_IN is low. See Figure 5
for suggested application circuit
E4 IRQ LM4930 mode status indicator pin
E5 I2S_WS I
2
S word select
E6 XTAL_OUT Negative feedback source for external crystal MCLK
F1 AGND_LS Analog ground for loudspeaker amplifier
F2 LS+ Loudspeaker amplifier BTL positive out (+)
F3 AVDD_LS Analog V
DD
for loudspeaker amplifier
F4 DGND_X Digital ground
F5 DVDD_X Digital V
DD
F6 MCLK/XTAL_IN 12.288MHz or 24.576MHz Master Clock from crystal (via XTAL OUT) or external source
LM4930
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System Control Registers
The LM4930 is controlled with a two-wire serial interface.
This interface is used to configure the operating mode, digi-
tal interfaces, and delta-sigma modulators. The LM4930 is
controlled by writing information into a series of write-only
registers, each with its own unique 7 bit address. The follow-
ing registers are programmable:
BASIC CONFIG REGISTER
This register is used to configure the I
2
S and PCM interfaces as well as the 48kHz DAC module. The 7 bit address for the
BASICCONFIG register is XX10000. (X=0ifADDR is set to logic 0) (X=1ifADDR is set to logic 1)
BASIC CONFIGURATION (XX1000). (Set = logic 1, Clear = logic 0)
BIT 15 14 131211109876543210
RESET 0 0 00000000000000
Address Register Description
3:0 MODE The LM4930 can be placed in one of several modes that dictate the basic operation. When a
new mode is selected the LM4930 will change operation silently and will re-configure the
power management profile automatically. The modes are described as follows: (Note 14)
Mode Mono Speaker
Amplifier Source
Headphone Left
Source
Headphone Right
Source
Comment
0000 None None None Powerdown mode
0001 None None None Standby mode
0010 Voice None None Mono speaker
mode
0011 None Voice Voice Headphone call
mode
0100 Voice Voice Voice Conference call
mode
0101 Audio (L+R) None None L+R mixed to
mono speaker
0110 None Audio (Left) Audio (Right) Headphone
stereo audio
0111 Audio (L+R) Audio (Left) Audio (Right) L+R mixed to
mono speaker +
stereo headphone
audio
1000 Audio (Left) Voice Voice Mixed Mode
1001 Voice + Audio
(Left)
Voice Voice Mixed mode
1010 Voice Audio (Left) Audio (Left) Mixed Mode
4 SOFT_RESET Resets the LM4930, excluding the control registers
5 PCM_LONG If set the PCM interface uses a long frame sync. (Note 12)
6 PCM_COMPANDED If set the 8 MSBs are presumed to be companded data and the 8 LSBs are ignored. (Note
12)
7 PCM_LAW If set, the companded G711 data is set to be A-law, else µ-law is assumed (Note 12)
8:9 PCM_SYNC_MODE Sets 1 (00h), 2 (01h) or 4(10h) 16 bit frames per sync. The PCM_SDO pin is tri-stated during
the latter frames. (Note 12)
10 PCM_ALWAYS_ON This bit should be set if another codec is using the PCM bus. When set, the LM4930 will
drive the clock and sync signals in all modes except Powerdown (Note 12)
11 I2S_M/S I2S master or slave select. If set then I2S = master. Cleared = slave
12 I2S_RES I2S resolution select. If set then 32 bits per frame. If cleared then 16 bits per frame
13 RSVD RESERVED (Note 13)
14 RSVD RESERVED (Note 13)
15 RSVD RESERVED (Note 13)
LM4930
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System Control Registers (Continued)
VOICE/TEST CONFIG REGISTERS
This register configures the voiceband codec, sidetone attenuation, and selected control functions. The 7 bit address for the
VOICE TESTCONFIG register is XX10001. (X=0ifADDR is set to logic 0) (X=1ifADDR is set to logic 1)
VOICETESTCONFIG (XX10001). (Set = logic 1, Clear = logic 0)
BIT 15 14 131211109876543210
RESET 0 0 00000000000000
Address Register Description
0 CLASS If set, configures the chip for use with an external class D or linear amplifier and turns the
BTL speaker output into a buffer. (Note 12)
4:1 SIDESTONE_ATTEN Programs the attenuation of the digital sidetone. Attenuation is set as follows:
4:1 Sidetone
Attenuation
4:1 Sidetone Attenuation
0000 Mute 1000 -9dB
0001 -30dB 1001 -6dB
0010 -27dB 1010 -3dB
0011 -24dB 1011 0dB
0100 -21dB 1100 Mute
0101 -18dB 1101 Mute
0110 -15dB 1110 Mute
0111 -12dB 1111 Mute
5 AUTOSIDE This feature is included for use with the mono speaker in hands-free applications where
sidetones may not be desirable. If set, the sidetone is always muted in modes when voice is
played on the mono speaker (0010, 0100, 1001, and 1010), otherwise the sidetone is present
at whatever level is set in the attenuation conrol register
6 CLOCK_DIV If set, allows for the use of a 24.576MHz crystal. Default setting is for 12.288MHz crystal.
(Note 12)
7 ZXD_DISABLE Disables the zero crossing detect in the stereo DAC to guarantee immediate mode changes
rather than waiting for a zero cross. (Note 11)
8:9 RSVD RESERVED (Note 13)
10:11 CAP_SIZE Set to accomodate different bypass capacitor values to give correct turn-off delay and
click/pop performance. Value is set as follows: (Note 12)
10:11 Delay Bypass Capacitor Size
00 25ms 0.1µF
01 50ms 0.39µF
10 85ms 1µF
11 RESERVED RESERVED
12 ZXDS_SLOW If set, this forces the stereo DAC outputs to wait for a zero crossing before powering down
13 MUTE_LS If set, mutes the loudspeaker amplifier in any mode where it is not already muted
14 MUTE_HP If set, mutes the headphone amplifier in any mode where it is not already muted
15 MUTE_MIC If set, mutes the microphone preamp
LM4930
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System Control Registers (Continued)
GAIN CONFIG REGISTERS
This register is used to control the gain of the headphone amplifier, the loudspeaker amplifier, and the microphone preampli-
fier. The 7 bit address for the GAINCONFIG register is XX10010. (X=0ifADDR is set to logic 0) (X=1ifADDR is set
to logic 1)
GAINCONFIG (XX10010). (Set = logic 1, Clear = logic 0)
BIT 15 14 131211109876543210
RESET 0 0 00000000000000
Address Register Description
4:0 LOUDSPKR_GAIN Programs the gain of the loudspeaker amplifier. Gain is set as follows:
4:0 Loudspeaker
Gain
4:0 Loudspeaker Gain
00000 -34.5dB 10000 -10.5dB
00001 -33dB 10001 -9dB
00010 -31.5dB 10010 -7.5dB
00011 -30dB 10011 -6dB
00100 -28.5dB 10100 -4.5dB
00101 -27dB 10101 -3dB
00110 -25.5dB 10110 -1.5dB
00111 -24dB 10111 0dB
01000 -22.5dB 11000 1.5dB
01001 -21dB 11001 3dB
01010 -19.5dB 11010 4.5dB
01011 -18dB 11011 6dB
01100 -16.5dB 11100 7.5dB
01101 -15dB 11101 9dB
01110 -13.5dB 11110 10.5dB
01111 -12dB 11111 12dB
9:5 HP_GAIN Programs the gain of the headphone amplifier. Gain is set as follows:
9:5 Headphone Gain 9:5 Headphone Gain
00000 -46dB 10000 -22.5dB
00001 -45dB 10001 -21dB
00010 -43.5dB 10010 -19.5dB
00011 -42db 10011 -18dB
00100 -40.5dB 10100 -16.5dB
00101 -39dB 10101 -15dB
00110 -37.5dB 10110 -13.5dB
00111 -36dB 10111 -12dB
01000 -34.5dB 11000 -10.5dB
01001 -33dB 11001 -9dB
01010 -31.5dB 11010 -7.5dB
01011 -30dB 11011 -6dB
01100 -28.5dB 11100 -4.5dB
01101 -27dB 11101 -3dB
01110 -25.5dB 11110 -1.5dB
01111 -24dB 11111 0dB
13:10 MIC_GAIN Programs the gain of the microphone amplifier. Gain is set as follows:
LM4930
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System Control Registers (Continued)
GAIN CONFIG REGISTERS (Continued)
13:10 Mic Preamp Gain
0000 17dB
0001 19dB
0010 21dB
0011 23dB
0100 25dB
0101 27dB
0110 29dB
0111 31dB
1000 33dB
1001 35dB
1010 37dB
1011 39dB
1100 41dB
1101 43dB
1110 45dB
1111 47dB
15:14 RSVD RESERVED (Note 13)
LM4930
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Timing Diagrams
20072009
FIGURE 2. Two-wire control Interface Timing Diagram
20072008
FIGURE 3. PCM Receive Timing Diagram
20072007
FIGURE 4. I
2
S Transmit Timing Diagram
LM4930
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Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Analog Supply Voltage 6.0V
Digital Storage Supply Voltage 6.0V
Storage temperature -65˚C to +150˚C
Power Dissipation (Note 3) Internally Limited
ESD Susceptibility
Human Body Model (Note 4) 2000V
Machine Model (Note 5) 200V
Junction temperature 150˚C
Thermal Resistance
θ
JA
- TLA36KRA 105˚C/W
θ
JA
- LQA44A (Note 17) 27˚C/W
Operating Ratings (Note 3)
Temperature Range
T
MIN
≤T
A
≤T
MAX
−30˚C ≤T
A
≤+85˚C
Supply Voltage
DV
DD
(Note 8) 2.6V - 4.5V
AV
DD
(Note 8) 2.6V - 5.5V
Electrical Characteristics DV
DD
= 3.3V, AV
DD
= 5V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 8)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
DI
DD
Digital Power Supply Current
f
MCLK
= 12.288MHz
Output Mode = "0010"
Output Mode = "0011"
Output Mode = "0100"
2
Output Mode = "0101"
Output Mode = "0110"
Output Mode = "0111"
4.4
Output Mode = "1000"
Output Mode = "1001"
Output Mode = "1010"
4.9 8 mA (max)
AI
DD
Analog Power Supply Quiescent
Current
f
MCLK
= 12.288MHz; No Load
Output Mode = "0010" 7.0
Output Mode = "0011" 6.3
Output Mode = "0100" 8.0
Output Mode = "0101" 8.2
Output Mode = "0110" 7.4
Output Mode = "0111" 8.7
Output Mode = "1000"
Output Mode = "1001"
Output Mode = "1010"
9.5 14 mA (max)
DI
SD
Digital Powerdown Current f
MCLK
= 12.288MHz
Output Mode = "0000" Powerdown Mode
1 7 µA (max)
AI
SD
Analog Powerdown Current f
MCLK
= 12.288MHz
Output Mode = "0000" Powerdown Mode 1 2 µA (max)
DI
ST
Digital Standby Current f
MCLK
= 12.288MHz
Output Mode = "0001" Standby Mode 1.4 2 mA (max)
AI
ST
Analog Standby Current f
MCLK
= 12.288MHz
Output Mode = "0001" Standby Mode 230 1000 µA (max)
V
FS_LS
Full-Scale Output Voltage
(Mono speaker amplifier)
CLASS = 0; 0dB gain setting; 8ΩBTL
load (Note 10)
2.5 V
P-P
V
FS_HP
Full-Scale Output Voltage
(Headphone amplifier)
0dB gain setting; 32ΩStereo Load (Note
10)
2.5 V
P-P
LM4930
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Electrical Characteristics DV
DD
= 3.3V, AV
DD
= 5V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 8) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
V
MIC_BIAS
Mic Bias Voltage 2.0 V
THD+N Headphone Amplifier Total
Harmonic Motion Distortion +
Noise
f
IN
= 1 kHz, P
OUT
= 7.5mW; 32ΩStereo
Load
0.07 %
P
OHP
Headphone Amplifier Output
Power
THD+N = 0.5%, f
OUT
= 1kHz 27 20 mW (min)
P
OLS
Mono Speaker Amplifier Output
Power
THD+N = 1%, f
OUT
= 1kHz 1 W
PSRR Power Supply Rejection Ratio C
BYPASS
= 1.0µF
C
DAC_REF
= 1.0µF
V
RIPPLE
= 200mV
P-P
@217Hz, MIC_P,
MIC_N terminated with 10Ωto ground
55 45 dB (min)
SNR
(Voice)
Signal-to-Noise Ratio
(Voice DAC Path)
Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise = digital zero,
A-weighted, 0dB gain setting
72 dB
SNR
(Music)
Signal-to-Noise Ratio (Music
Audio Path)
Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise = digital zero,
A-weighted; 0dB gain setting
86 dB
DR
(Voice)
Dynamic Range (Voice DAC Path) Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise for -60dBFS
digital input; A-weighted; 0dB gain setting
72 dB
DR
(Music)
Dynamic Range (Music Audio
Path)
Signal = Vo at f=1kHz @1% THD+N, 32Ω
Stereo Load; Noise for -60dBFS digital
input; A-weighted, 0dB gain setting
86 dB
SNR
ADC
Signal-to-Noise Ratio
(Voice ADC Path)
Reference signal = 0dBFS
MIC_P, MIC_N terminated with 10Ωto
ground;
A-weighted; 47dB MIC preamp gain
setting
75 dB
DR
ADC
Dynamic Range
(Voice ADC Path)
Reference signal = 0dBFS
Noise for -60dBFS digital input;
A-weighted; 47dB MIC preamp gain
setting
75 dB
X
TALK
Stereo Channel-to-Channel
Crosstalk
f
S
= 48kHz, f
IN
= 1kHz sinewave at
-3dB
FS
75 dB
V
MIC-IN
Maximum Differential MIC Input
Voltage
17dB MIC Preamp gain setting 570 mV
P-P
R
VDAC
Voice DAC Ripple 300Hz - 3.3kHz through head-phone
output.
+/-0.15 +/-0.2 dB (max)
R
VADC
Voice ADC Ripple 300Hz - 3.3kHz through head-phone
output.
+/-0.25 +/-0.3 dB (max)
PB
VDAC
Voice DAC Passband -3dB Point 3.46 kHz
SBA
VDAC
Voice DAC Stopband Attenuation Above 4kHz 72 dB
UPB
VADC
Voice ADC Upper Passband
Cutoff Frequency.
Upper -3dB Point 3.47 kHz
LM4930
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Electrical Characteristics DV
DD
= 3.3V, AV
DD
= 5V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 8) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
LPB
VADC
Voice ADC Lower Passband
Cutoff Frequency.
Lower -3dB Point 0.230 kHz
SBA
VADC
Voice ADC Stopband Attenuation Above 4kHz 65 dB
SBA
NOTCH
Voice ADC Notch Attenuation Centered on 55Hz, figure gives worst
case attenuation for 50Hz & 60Hz.
58 dB
R
DAC
Audio DAC Ripple 20Hz - 20kHz through head-phone output. +/-0.1 +/-0.2 dB (max)
PB
DAC
Audio DAC Passband Width -3dB point 22.7 kHz
SBA
DAC
Audio DAC Stopband Attenuation Above 24kHz 76 dB
DR
DAC
Audio DAC Dynamic Range
Digital Filter Section
Signal = VO at f = 1kHz @1% THD+N;
f = 1kHz; Noise for -60dBFS digital input;
0dB gain; A-weighted
97 dB
SNR
DAC
Audio DAC SNR Digital Filter
Section
Signal = VO at f = 1kHz @1% THD+N;
f = 1kHz; Noise for -60dBFS digital input;
0dB gain; A-weighted
97 dB
∆A
CH-CH
Stereo Channel-to-Channel Gain
Mismatch
0.3 dB
V
IL
Digital Input: Logic Low Voltage
Level
0.4 V
V
IH
Digital Input: Logic High Voltage
Level
1.4 V
Volume Control Range
(Headphone amplifiers)
Maximum Attenuation
Minimum Attenuation
-46.5
0
dB
dB
Volume Control Range (Mono
speaker amplifier)
Minimum Gain
Maximum Gain
-34.5
12
dB
dB
Volume Control Step Size (Output
amplifiers)
1.5 dB
Volume Control Range
(Microphone Preamp)
Minimum Gain
Maximum Gain
17
47
dB
dB
Volume Control Step Size
(Microphone Preamp)
2dB
Side Tone Attenuation Range Maximum Attenuation
Minimum Attenuation
-30
0
dB
dB
Side Tone Attenuation Step Size 3 dB
f
MCLK
MCLK frequency CLOCK_DIV = 0
CLOCK_DIV = 1
12.288
24.576
MHz
MHz
MCLK Duty Cycle 50 40
60
% (min)
% (max)
f
CONV
Sampling Clock Frequency (Note
9)
48 kHz
f
CLKSCL
SCL_CLK Frequency 400 kHz
t
RISESCL
SCL_CLK, SCL_DATA Rise Time 300 ns
t
FALLSCL
SCL_CLK, SDA_DATA Fall Time 300 ns
t
SDAH
SDA_DATA Hold Time 500 ns
t
SDAS
SDA_DATA Setup Time 500 ns
LM4930
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Electrical Characteristics DV
DD
= 3.3V, AV
DD
= 5V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 8) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
f
CLKPCM
PCM_CLK Frequency PCM_SYNC_MODE = 00
PCM_SYNC_MODE = 01
PCM_SYNC_MODE = 10
128
256
512
kHz
PCM_CLK Duty Cycle 50 40
60
% (min)
% (max)
f
CLKI2S
I2S_CLK Frequency I2S_RES = 0
I2S_RES = 1
1.536
3.072
MHz
I2S_CLK Duty Cycle 50 40
60
% (min)
% (max)
Electrical Characteristics DV
DD
= 3V, AV
DD
= 3V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 3)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
DI
DD
Digital Power Supply Current
f
MCLK
= 12.288MHz
Output Mode = "0010"
Output Mode = "0011"
Output Mode = "0100"
1.6
Output Mode = "0101"
Output Mode = "0110"
Output Mode = "0111"
3.8
Output Mode = "1000"
Output Mode = "1001"
Output Mode = "1010"
4.2 7 mA (max)
AI
DD
Analog Power Supply Quiescent
Current
f
MCLK
= 12.288MHz; No Load
Output Mode = "0010" 5.8
Output Mode = "0011" 5.1
Output Mode = "0100" 6.5
Output Mode = "0101" 6.4
Output Mode = "0110" 5.8
Output Mode = "0111" 7.0
Output Mode = "1000"
Output Mode = "1001"
Output Mode = "1010"
7.5 12 mA (max)
DI
SD
Digital Powerdown Current f
MCLK
= 12.288MHz
Output Mode = "0000" Powerdown Mode
1 7 µA (max)
AI
SD
Analog Powerdown Current f
MCLK
= 12.288MHz
Output Mode = "0000" Powerdown Mode 0.6 1.5 µA (max)
DI
ST
Digital Standby Current f
MCLK
= 12.288MHz
Output Mode = "0001" Standby Mode 1.1 1.7 mA (max)
LM4930
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Electrical Characteristics DV
DD
= 3V, AV
DD
= 3V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 3) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
AI
ST
Analog Standby Current f
MCLK
= 12.288MHz
Output Mode = "0001" Standby Mode 100 300 µA (max)
V
FS_LS
Full-Scale Output Voltage
(Mono speaker amplifier)
CLASS = 0; 0dB gain setting; 8ΩBTL
load (Note 10)
2.5 V
P-P
V
FS_HP
Full-Scale Output Voltage
(Headphone amplifier)
0dB gain setting; 32ΩStereo Load (Note
10)
2.5 V
P-P
V
MIC_BIAS
Mic Bias Voltage 2 V
THD+N Headphone Amplifier Total
Harmonic Distortion + Noise
f
IN
= 1kHz, P
OUT
= 7.5mW 0.07 %
P
OHP
Headphone Amplifier Output
Power
THD+N = 0.5%, f
OUT
= 1kHz 25 15 mW (min)
P
OLS
Mono Speaker Amplifier Output
Power
THD+N = 1%, f
OUT
= 1kHz 330 270 mW (min)
PSRR Power Supply Rejection Ratio C
BYPASS
= 1.0µF
C
DAC_REF
= 1.0µF
V
RIPPLE
= 200mV
P-P
@217Hz
50 42 dB (min)
SNR
(Voice)
Signal-to-Noise Ratio
(Voice DAC Path)
Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise = digital zero,
A-weighted; 0dB gain setting
72 dB
SNR
(Music)
Signal-to-Noise Ratio (Music
Audio Path)
Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise = digital zero,
A-weighted; 0dB gain setting
86 dB
DR
(Voice)
Dynamic Range (Voice DAC Path) Signal = Vo at f = 1kHz @1% THD+N,
32ΩStereo Load; Noise for -60dBFS
digital input; A-weighted, 0dB gain setting
72 dB
DR
(Music)
Dynamic Range (Music Audio
Path)
Signal = Vo at f=1kHz @1% THD+N, 32Ω
Stereo Load; Noise for -60dBFS digital
input; A-weighted, 0dB gain setting
86 dB
SNR
ADC
Signal-to-Noise Ratio
(Voice ADC Path)
Reference signal = 0dBFS
MIC_P, MIC_N terminated with 10Ωto
ground;
A-weighted; 47dB MIC preamp gain
setting
75 dB
DR
ADC
Dynamic Range
(Voice ADC Path)
Reference signal = 0dBFS
Noise for -60dBFS digital input;
A-weighted; 47dB MIC preamp gain
setting
75 dB
X
TALK
Stereo Channel-to-Channel
Crosstalk
f
S
= 48kHz, f
IN
= 1kHz sinewave at
-3dB
FS
73 dB
V
MIC-IN
Maximum Differential MIC Input
Voltage
17dB MIC Preamp gain setting 570 mV
P-P
R
VDAC
Voice DAC Ripple 300Hz - 3.3kHz through head-phone
output.
+/-0.15 +/-0.2 dB (max)
R
VADC
Voice ADC Ripple 300Hz - 3.3kHz through head-phone
output.
+/-0.25 +/-0.3 dB (max)
PB
VDAC
Voice DAC Passband -3dB Point 3.46 kHz
LM4930
www.national.com 14
Electrical Characteristics DV
DD
= 3V, AV
DD
= 3V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 3) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
SBA
VDAC
Voice DAC Stopband Attenuation Above 4kHz 72 dB
UPB
VADC
Voice ADC Upper Passband
Cutoff Frequency.
Upper -3dB Point 3.47 kHz
LPB
VADC
Voice ADC Lower Passband
Cutoff Frequency.
Lower -3dB Point 0.230 kHz
SBA
VADC
Voice ADC Stopband Attenuation Above 4kHz 65 dB
SBA
NOTCH
Voice ADC Notch Attenuation Centered on 55Hz, figure gives worst
case attenuation for 50Hz & 60Hz.
58 dB
R
DAC
Audio DAC Ripple 20Hz - 20kHz through head-phone output. +/-0.1 +/-0.2 dB (max)
PB
DAC
Audio DAC Passband Width -3dB point 22.7 kHz
SBA
DAC
Audio DAC Stopband Attenuation Above 24kHz 76 dB
DR
DAC
Audio DAC Dynamic Range
Digital Filter Section
Signal = VO at f = 1kHz @1% THD+N;
f = 1kHz; Noise for -60dBFS digital input;
0dB gain; A-weighted
97 dB
SNR
DAC
Audio DAC SNR Digital Filter
Section
Signal = VO at f = 1kHz @1% THD+N;
f = 1kHz; Noise for -60dBFS digital input;
0dB gain; A-weighted
97 dB
∆A
CH-CH
Stereo Channel-to-Channel Gain
Mismatch
0.3 dB
V
IL
Digital Input: Logic Low Voltage
Level
0.4 V
V
IH
Digital Input: Logic High Voltage
Level
1.4 V
Volume Control Range
(Headphone amplifiers)
Maximum Attenuation
Minimum Attenuation
-46.5
0
dB
dB
Volume Control Range (Mono
speaker amplifier)
Minimum Gain
Maximum Gain
-34.5
12
dB
dB
Volume Control Step Size (Output
amplifiers)
1.5 dB
Volume Control Range
(Microphone Preamp)
Minimum Gain
Maximum Gain
17
47
dB
Volume Control Step Size
(Microphone Preamp)
2dB
Side Tone Attenuation Range Maximum Attenuation
Minimum Attenuation
-30
0
dB
dB
Side Tone Attenuation Step Size 3 dB
f
MCLK
MCLK frequency CLOCK_DIV = 0
CLOCK_DIV = 1
12.288
24.576
MHz
MHz
MCLK Duty Cycle 50 40
60
% (min)
% (max)
f
CONV
Sampling Clock Frequency (Note 9) 48 kHz
f
CLKSCL
SCL_CLK Frequency 400 kHz
t
RISESCL
SCL_CLK, SCL_DATA Rise Time 300 ns
t
FALLSCL
SCL_CLK, SDA_DATA Fall Time 300 ns
t
SDAH
SDA_DATA Hold Time 500 ns
LM4930
www.national.com15
Electrical Characteristics DV
DD
= 3V, AV
DD
= 3V, R
LHP
=32Ω,R
LHF
=8Ω
(Notes 1, 2, 3) (Continued)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25˚C.
Symbol Parameter Conditions LM4930 Units
(Limits)
Typical
(Note 6)
Limits
(Notes 7,
15)
t
SDAS
SDA_DATA Setup Time 500 ns
f
CLKPCM
PCM_CLK Frequency PCM_SYNC_MODE = 00
PCM_SYNC_MODE = 01
PCM_SYNC_MODE = 10
128
256
512
kHz
kHz
kHz
PCM_CLK Duty Cycle 50 40
60
% (min)
% (max)
f
CLKI2S
I2S_CLK Frequency I2S_RES = 0
I2S_RES = 1
1.536
3.072
MHz
MHz
I2S_CLK Duty Cycle 50 40
60
% (min)
% (max)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which
guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit
is given, however, the typical value is a good indication of device performance.
Note 2: All voltages are measured with respect to the relevant GND pin unless otherwise specified.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX ,θJA, and the ambient temperature, TA. The maximum
allowable power dissipation is PDMAX =(T
JMAX –T
A)/θJA or the number given in Absolute Maximum Ratings, whichever is lower. For the LM4930, see power
derating currents for more information.
Note 4: Human body model: 100pF discharged through a 1.5kΩresistor.
Note 5: Machine model: 220pF - 240pF discharged through all pins.
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Best operation is achieved by maintaining 3.0V ≤AVDD ≤5.0 and 3.0V ≤DVDD ≤3.6V. AVDD must be equal to or greater than DVDD. for proper operation.
Note 9: The sampling clock frequency is equal to the master clock frequency divided by 256. (fconv =f
MCLK/256)
Note 10: This value represents the 0dB output level of the given amplifier for the given analog supply voltage. Gain values given in the GAINCONFIG register are
relative to these full-scale values for each output amplifier.
Note 11: To ensure a successful transistion into Powerdown Mode, ZXD_DISABLE must be set whenever there is no audio input signal present.
Note 12: It is recommended to alter this bit only while the part is in Powerdown Mode.
Note 13: Reserved bits should be set to zero when programming the associated register.
Note 14: With the exception of Standby Mode, rapid switching between modes should be avoided. Rapid switching between modes will not ensure that the desired
mode will be activated.
Note 15: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 16: 0dBm0 = -3dBFS for the PCM voice codec and 0dBm0 = -1dBFS for the I2S DAC, unless otherwise specified.
Note 17: The given θAis for an LM4930 packaged in an LQA44A with the Exposed-DAP soldered to an exposed 2in2area of 1oz printed circuit board copper with
16 thermal vias as described in National AN-1187.
LM4930
www.national.com 16
Typical Performance Characteristics (Note 16)
MIC PreAmp + ADC Frequency Response
(MIC Gain = 17dB)
MIC PreAmp + ADC Frequency Response Zoom
(MIC Gain = 17dB)
20072015 20072016
MIC PreAmp + ADC Frequency Response
(MIC Gain = 47dB)
MIC PreAmp + ADC Frequency Response Zoom
(MIC Gain = 47dB)
20072017 20072018
MIC PreAmp + ADC Frequency Response High Cutoff
(MIC Gain = 17dB)
MIC PreAmp + ADC Frequency Response High Cutoff
(MIC Gain = 47dB)
20072019 20072020
LM4930
www.national.com17
Typical Performance Characteristics (Note 16) (Continued)
MIC PreAmp + ADC Frequency Response Low Cutoff
(MIC Gain = 17dB)
MIC PreAmp + ADC Frequency Response Low Cutoff
(MIC Gain = 47dB)
20072021 20072022
ADC THD+N vs MIC Input Voltage
(MIC Gain = 17dB)
ADC THD+N vs MIC Input Voltage
(MIC Gain = 47dB)
20072023 20072024
MIC PreAmp + ADC PSRR vs Frequency
Top Trace = 47dB MIC Gain, Bottom Trace = 17dB MIC
Gain
Headphone Sense In Hysteresis Loop
(AV
DD
= 3V)
20072026 20072027
LM4930
www.national.com 18
Typical Performance Characteristics (Note 16) (Continued)
Headphone Sense In Hysteresis Loop
(AV
DD
= 5V)
I
2
S DAC Frequency Response
( Handsfree Output)
20072028 20072029
I
2
S DAC Frequency Response Zoom
(Handsfree Output)
I
2
S DAC Frequency Response Zoom
(Headphone Output)
20072030 20072031
I
2
S DAC Frequency Response Zoom
(Headphone Output)
THD+N vs I
2
S Input Voltage
(Handsfree Output, 0dB Handsfree Gain)
20072032 20072038
LM4930
www.national.com19
Typical Performance Characteristics (Note 16) (Continued)
THD+N vs I
2
S Input Voltage
(Headphone Output, 0dB Headphone Gain)
I
2
S DAC Crosstalk
(Top Trace = Left to Right, Bottom Trace = Right to Left)
20072039 20072040
MIC Bias Dropout Voltage vs
MIC Bias Current
PCM DAC Frequency Response
(Handsfree Output)
20072041
20072055
PCM DAC Frequency Response Zoom
(Handsfree Output)
PCM DAC Frequency Response
(Headphone Output)
20072049
20072050
LM4930
www.national.com 20
Typical Performance Characteristics (Note 16) (Continued)
PCM DAC Frequency Response Zoom
(Headphone Output)
THD+N vs PCM Input Voltage
(Handsfree Output, 0dB Handsfree Gain)
20072051 20072052
THD+N vs PCM Input Voltage
(Headphone Output, 0dB Headphone Gain)
Crosstalk
(AV
DD
= 5V and AV
DD
= 3V, Headphone Output)
20072053 200720F9
PSRR vs Frequency
(AV
DD
= 3V, R
L
=16Ω, Headphone Output)
PSRR vs Frequency
(AV
DD
= 3V, R
L
=32Ω, Headphone Output)
200720G0 200720G1
LM4930
www.national.com21
Typical Performance Characteristics (Note 16) (Continued)
PSRR vs Frequency
(AV
DD
= 3V, R
L
=8Ω, Handsfree Output)
PSRR vs Frequency
(AV
DD
= 5V, R
L
=16Ω, Headphone Output)
200720G2 200720G3
PSRR vs Frequency
(AV
DD
= 5V, R
L
=32Ω, Headphone Output)
PSRR vs Frequency
(AV
DD
= 5V, R
L
=8Ω, Handsfree Output)
200720G4 200720G5
THD+N vs Frequency
(AV
DD
= 3V, R
L
=8Ω,P
O
= 150mW, Handsfree Output)
THD+N vs Frequency
(AV
DD
= 5V and AV
DD
= 3V, R
L
=16Ω,P
O
= 15mW,
Headphone Output)
20072001
200720G7
LM4930
www.national.com 22
Typical Performance Characteristics (Note 16) (Continued)
THD+N vs Frequency
(AV
DD
= 5V and AV
DD
= 3V, R
L
=32Ω,P
O
= 7.5mW,
Headphone Output)
THD+N vs Frequency
(AV
DD
= 5V, R
L
=8Ω,P
O
= 250mW, Handsfree Output)
200720G8 20072025
THD+N vs Output Power
AV
DD
= 3V, R
L
=16Ω, f = 1kHz, Headphone Output)
THD+N vs Output Power
(AV
DD
= 3V, R
L
=8Ω, f = 1kHz, Handsfree Output)
200720H0
20072033
THD+N vs Output Power
(AV
DD
= 5V and AV
DD
= 3V, R
L
=32Ω, f = 1kHz,
Headphone Output)
THD+N vs Output Power
(AV
DD
= 5V and AV
DD
= 3V, R
L
=16Ω, f = 1kHz,
Headphone Output)
200720H3 200720H4
LM4930
www.national.com23
Application Information (Continued)
20072006
FIGURE 6. LM4930ITL Demo Board Composite View
20072005
FIGURE 7. LM4930ITL Demo Board Silkscreen
LM4930
www.national.com25
Application Information (Continued)
20072004
FIGURE 8. LM4930ITL Demo Board Top Layer
20072013
FIGURE 9. LM4930ITL Demo Board Bottom Layer
LM4930
www.national.com 26
Application Information (Continued)
20072012
FIGURE 10. LM4930ITL Demo Board Inner Layer 1
20072011
FIGURE 11. LM4930ITL Demo Board Inner Layer 2
LM4930
www.national.com27
Application Information (Continued)
BILL OF MATERIALS FOR LM4930
LM4930 Demo Board Bill Of Materials
Comment Footprint Designators
1k 0805 R6, R7
2k 0805 R2, R3
20k 0805 R1
100k 0805 R5
1M 0805 R4
22pF 1210 C6, C7
0.01µF cer 1210 C16, C17
0.1µF cer 1210 C14, C15
1µF 1210 C1, C2, C3, C4, C5, C10, C11,
C12, C13
220µF 7243 C8, C9
CRYSTAL 7243 Y1
PHONE JACK STEREO SW STEREO HEADPHONE JACK (3.5MM) J8
20072010
FIGURE 12. Pin Markings for LM4930ITL demo board
LM4930
www.national.com 28
Application Information (Continued)
Two-wire control Interface (J1)
Pin Function
1 DVDD
2 SCL
3 DGND
4NC
5 DGND
6 SDA
PCM Interface (P4, P3, P1, P2)
Header Function
P1 PCM_SDI
P2 PCM_CLK
P3 PCM_SYNC
P4 PCM_SDO
I2S Interface (J2)
Pin Function
1 MCLK
2 I2S-CLK
3 I2S-DATA
4 I2S-WS
5 DGND
6 DGND
7 DGND
8 DGND
9 DGND
10 DGND
MIC Jack
Pin Function
1 AGND
2 MIC-
3 MIC+
Misc Jumpers and Headers
DVDD/DGND (J10)
Pin Function
1 DGND
2 AVDD
Misc Jumpers and Headers
AVDD/AGND (J9)
Pin Function
1 AGND
2 AVDD
Misc Jumpers and Headers
MCLK/XTAL_IN (P5)
Pin Function
LM4930
www.national.com29
Application Information (Continued)
Misc Jumpers and Headers
MCLK/XTAL_IN (P5) (Continued)
1 DGND
2 MCLK/XTAL_IN
ADR SELECT (S1)
Jumper IN = LOW
Control interface responds to addresses 001000b (BASICCONFIG), 0010001b (VOICETESTCONFIG)), and 0010010b (GAIN-
CONFIG)
Jumper OUT = HIGH
Control interface responds to addresses 111000b (BASICCONFIG), 1110001b (VOICETESTCONFIG)), and 1110010b (GAIN-
CONFIG)
HP Sense Out (J6)
Pin Function
1 AGND
2 HPSense_Out
IRQ (J4)
Pin Function
1 DGND
2 IRQ
Onboard MCLK Select (S2)
Jumper IN = Onboard MCLK
Jumper OUT = External MCLK
LM4930ITL DEMO BOARD OPERATION
The LM4930ITL demo board is a complete evaluation plat-
form, designed to give easy access to the control pins of the
part and comprise all the necessary external passive com-
ponents. Besides the separate analog (J9) and digital (J10)
supply connectors, the board features seven other major
input and control blocks: a two wire interface bus (J1) for the
control lines, a PCM interface bus (P1-P4) for voiceband
digital audio, an I2S interface bus (J2) for full-range digital
audio, an analog mic jack input (J3) for connection to an
external microphone, a BTL mono output (J7) for connection
to an external speaker, a stereo headphone output (J8), and
an external MCLK input (P5) for use in place of the crystal on
the demoboard.
Two-wire Interface Bus (J1)
This is the main control bus for the LM4930. It is a two-wire
interface with an SDA line (data) and SCL line (clock). Each
transmission from the baseband controller to the LM4930 is
given MSB first and must follow the timing intervals given in
the Electrical Characteristics section of the datasheet to
create the start and stop conditions for a proper transmis-
sion. The start condition is detected if SCL is high on the
falling edge of SDA. The stop condition is detected if SCL is
high on the rising edge of SDA. Repeated start signals are
handled correctly. Data is then transmitted as shown in
Figure 2. After the start condition has been achieved the chip
address is sent, followed by a set write bit, wait for ack (SDA
will be pulled low by LM4930), data bits 15-8, wait for ACK
(SDA will be pulled low by LM4930), data bits 7-0, wait for
ACK (SDA will be pulled low by LM4930)and finally the stop
condition is given.
This same sequence follows for any control bus transmis-
sion to the LM4930. The chip address is hardwire selected
by the ADR Select pin which may be jumpered high or low
with its application at S1 on the demo board. The chip
address is then given as a combination of the identifying bits
for the LM4930 plus the 2-bit address of the desired control
register (00b = BasicConfig, 01b = VoicetestConfig, 10b =
GainConfig). Acceptable addresses are shown here in Table
1.
Table 1. LM4930 Control Bus Addresses
Address Bits Register
Address
ADR=0
6543210
0010000
0010001
0010010
ADR=1
1110000
1110001
1110010
Data is sampled only if the address is in range and the R/W
bit is clear. Data for each register is given in the System
Control Registers section of the datasheet. National Semi-
conductor also features a special control board for quick
evaluation of the LM4930 demo board with your PC. This is
a serial control interface board, complete with header com-
LM4930
www.national.com 30
Application Information (Continued)
patible with the interface header (J1) on the LM4930 board.
This also features demonstration software to allow for com-
plete control and evaluation of the various modes and func-
tions of the LM4930 through the bus.
Pullup resistors are required to achieve reliable operation.
750Ωpullup resistors on the SDA and SCL lines achieves
best results when used with National’s parallel-to-serial in-
terface board. Lower value pullup resistors will decrease the
rise and fall times on the bus which will in turn decrease
susceptibility to bus noise that may cause a false trigger. The
cost comes at extra current use. Control bus reliability will
thus depend largely on bus noise and may vary from design
to design. Low noise is critical for reliable operation.
PCM Bus Interface (P1, P2, P3, P4)
PCM_SDO (P4), PCM_SYNC (P3), PCM_SDI (P1), and
PCM_CLK (P2) form the PCM interface bus for simple com-
munication with most baseband ICs with voiceband commu-
nications and follow the PCM-1900 communications stan-
dard. The PCM interface features frame lengths of 16, 32, or
64 bits, A-law and u-law companding, linear mode, short or
long frame sync, an energy-saving power down mode, and
master only operation.
The PCM bus does not support a slave mode. It operates as
a master only. Thus PCM_SYNC and PCM_CLK are solely
generated by the LM4930. PCM_SYNC is the word sync line
for the bus. It operates at a fixed frequency of 8kHz and may
be set in the BASICCONFIG register (bit 5 PCM_LONG) for
short or long frame sync. A short frame sync is 1 PCM_CLK
cycle (PCM_LONG=0), a long frame sync is 2 PCM_CLK
cycles long (PCM_LONG=1). A long sync pulse is also de-
layed one clock cycle relative to a short sync pulse. This is
illustrated in Figure 3. PCM_CLK is the bit clock for the bus.
It’s frequency depends on the number of 16-bit frames per
sync pulse and can be 128kHz, 256kHz, 512kHz.
The other two lines, PCM_SDO and PCM_SDI, are for serial
data out and serial data in, respectively. The type of data
may also be set in the BASICCONFIG register by bits 6 and
7. Bit 6 controls whether the data is linear or companded. If
set to 1, the 8 MSBs are presumed to be companded data
and the 8 LSBs are ignored. If cleared to 0, the data is
treated as 2’s complement PCM data. Bit 7 controls which
PCM law is used if Bit 6 is set for companded (G711) data. If
set to 1, the companded data is assumed to be A-law. If
cleared to 0, the companded data is treated as µ-law.
Bits 8:9 of the BASICCONFIG register set the PCM_SYNC-
_MODE settings. This controls the number of 16 bit frames
per sync pulse. The feature allows the LM4930 to function
harmoniously with other devices or channels on the PCM
bus by adjusting the number of 16 bit frames per sync pulse
to 1 (00b), 2 (01b), or 4 (10b). The LM4930 will transmit PCM
data in the first frame and then tri-state the PCM_SDO pin on
later frames.
In addition, the LM4930 provides control to allow the PCM-
_CLK and PCM_SYNC clocks to continue functioning even
when the LM4930 is in Standby mode. By setting bit 10 of
the BASICCONFIG register to 1 PCM_ALWAYS_ON is en-
abled and the LM4930 will continue to drive the PCM clock
and sync lines when in Standby mode. This bit should be set
if another codec is using the PCM bus. Powerdown mode
will disable these outputs.
I2S Interface Bus (J2)
The I2S standard provides a uni-directional serial interface
designed specifically for digital audio. For the LM4930, the
interface provides access to a 48kHz, 16 bit full-range stereo
audio DAC. This interface uses a three port system of clock
(I2S_CLK), data (I2S_DATA), and word (I2S_WS). The clock
and word lines can be either master or slave as set by bit 11
in the BASICCONFIG register.
A bit clock (I2S_CLK) at 32 or 64 times the sample frequency
is established by the I2S system master and a word select
(I2S_WS) line is driven at a frequency equal to the sampling
rate of the audio data, in this case 48kHz. The word line is
registered to change on the negative edge of the bit clock.
The serial data (I2S_DATA) is sent MSB first, again regis-
tered on the negative edge of the bit clock, delayed by 1 bit
clock cycle relative to the changing of the word line (typical
I2S format - see Figure 4).
The resolution of the I2S interface may be set by modifying
the I2S_RES bit (bit 12) in the BASICCONFIG register. If set
to 1, the LM4930 operates at 32 bits per frame (3.072MHz).
If cleared to 0, then 16 bits per frame is selected
(1.536MHz). This has a corresponding effect on the bit clock.
The I2S Interface Bus also provides for an additional MCLK
connection to an external device from the LM4930 demo
board. This may be used in conjunction with National Semi-
conductors SPDIF->I2S Conversion Board for quick evalu-
ation. This board features a connection header that inter-
faces with pins 1-5 of the I2S Interface Bus. Pins 6-10 are
provided as digital ground references for the case of discrete
connections.
MCLK/XTAL_IN (P5)
This is the input for an external Master Clock. The jumper at
S2 must be removed (disconnecting the onboard crystal
from the circuit) when using an external Master Clock.
BTL Mono Out (J7)
This is the mono speaker output, designed for use with an 8
ohm speaker. The outputs are driven in bridge-tied-load
(BTL) mode, so both sides have signal. Outputs are normally
biased at one half AVDD when the LM4930 is in active mode.
Additionally, if the CLASS bit is set to 1 in the VOICETEST-
CONFIG register (bit 0) the BTL mono output is internally
configured as a buffer amplifier designed for use with an
external class D amp.
Stereo Headphone Out (J8)
This is the stereo headphone output. Each channel is single-
ended, with 220uF DC blocking capacitors mounted on the
demo board. The jack features a typical stereo headphone
pinout.
A headphone sense pin is provided at J6. This pin provides
a clean logic high or low output to indicate the presence of
headphones in the headphone jack. A common application
circuit for this is given in the Reference Board Schematic
shown in Figure 5. In this application HPSENSE_IN is pulled
low by the 1k ohm resistor when no headphone is present.
This gives a corresponding logic low output on the
HPSENSE_OUT pin. When a headphone is placed in the
jack the 1k ohm pull-down is disconnected and a 100k ohm
pull-up resistor creates a high voltage condition on
HPSENSE_IN. This in turn creates a logic high on
HPSENSE_OUT. This output may be used to reliably drive
an external microcontroller with headphone status.
LM4930
www.national.com31
Application Information (Continued)
MIC Jack (J3)
This jack is for connection to an external microphone like the
kind typically found in mobile phones. Pin 1 is GND, pin 2 is
the negative input pin, and pin 3 is the positive pin, with
phantom voltage supplied by MIC_BIAS on the LM4930.
IRQ (J4)
This pin provides simple status updates from the LM4930 to
an external microcontroller if desired. IRQ is logic high when
the LM4930 is in a stable state and changes to low when
changing modes. This can also be useful for simple
software/driver development to monitor mode changes, or as
a simple debugging tool.
BASIC OPERATION
The LM4930 is a highly integrated audio subsystem with
many different operating modes available. These modes
may be controlled in the BASICCONFIG register in bits 3:0.
These mode settings are shown in the BASICCONFIG reg-
ister table and are described here below:
Powerdown Mode (0000b)
Part is powered down, analog outputs are not biased. This is
a minimum current mode. All part features are shut down.
Standby Mode (0001b)
The LM4930 is powered down, but outputs are still biased at
one half AVDD. This comes at some current cost, but pro-
vides a much faster turn-on time with zero "click and pop"
transients on the headphone out. Standby mode can be
toggled into and out of rapidly and is ideal for saving power
whenever continuous audio is not a requirement. All other
part functions are suspended unless PCM_ALWAYS_ON (bit
10 in BASICCONFIG register) is enabled, in which case
PCM_CLK and PCM_SYNC will continue to function.
Mono Speaker Mode (0010b)
Part is active. All analog outputs are biased. Audio from the
voiceband codec is routed to the mono speaker out. Stereo
headphone out is silent.
Headphone Call Mode (0011b)
Part is active. All analog outputs are biased. Audio from
voiceband codec is routed to the stereo headphones. Both
left and right channels are the same. Mono speaker out is
silent.
Conference Call Mode (0100b)
Part is active. All analog outputs are biased. Audio from the
voiceband codec is routed to the mono speaker out and to
the stereo headphones.
L+R Mixed to Mono Speaker (0101b)
Part is active. All analog outputs are biased. Full-range audio
from the 16bit/48kHz audio DAC is mixed together and
routed to the mono speaker out. Stereo headphones are
silent.
Headphone Stereo Audio (0110b)
Part is active. All analog outputs are biased. Full-range audio
from the 16bit/48kHz audio DAC is sent to the stereo head-
phone jack. Each channel is heard discretely. The mono
speaker is silent.
L+R Mixed to Mono Speaker + Stereo Headphone
Audio (0111b)
Part is active. All analog outputs are biased. Full-range audio
from the 16bit/48kHz audio DAC is sent discretely to the
stereo headphone jack and also mixed together and sent to
the mono speaker out.
Mixed Mode (1000b)
Part is active. All analog outputs are biased. This provides
one channel (the left channel) of full range audio to the mono
speaker out. Audio from the voiceband codec is then sent to
the stereo headphones, the same on each channel.
Mixed Mode (1001b)
Part is active. All analog outputs are biased. Mixed voice-
band and full-range audio (left channel only) is sent to the
mono speaker out. Audio from the voiceband codec only is
sent to the stereo headphones, the same on each channel.
Mixed Mode (1010b)
Part is active. All analog outputs are biased. Audio from the
voiceband codec is sent to the mono speaker out. The left
channel only of the full range audio is then sent to both the
left and right channels of the stereo headphone out.
REGISTERS
The LM4930 starts on power-up with all registers cleared in
Powerdown mode. Powerdown mode is the recommended
time to make setup changes to the digital interfaces (PCM
bus, I2S bus). Although the configuration registers can be
changed in any mode, changes made during Standby or
Powerdown prevent unwanted audio artifacts that may occur
during rapid mode changes with the outputs active. The
LM4930 also features a soft reset. This reset is enabled by
setting bit 4 of the BASICCONFIG register.
The VOICETESTCONFIG register is used to set various
configuration parameters on the voiceband and full-range
audio codecs. SIDETONE_ATTEN (bits 4:1) refers to the
level of signal from the MIC input that is fed back into the
analog audio output path (commonly used in headphone
applications and killed in hands-free applications). Setting
the AUTOSIDE bit (bit 5) automatically mutes the sidetone in
voice over mono speaker modes so feedback isn’t an issue.
Quick mute functions are also located in this register, with
bits 13:15 muting the mono speaker amp, the headphone
amp, and the mic preamp respectively.
This register also has a CLOCK_DIV bit (bit 6) which, if set,
allows for the use of a 24.576MHz clock instead of the
default 12.288MHz.
The GAINCONFIG register is used to control the gain of the
mono speaker amp , the headphone amp, and the mic
preamp. This allows flexible mono speaker gains from
-34.5dB to +12dB in 1.5dB steps, headphone amp gains of
-46.5dB to 0dB in 1.5dB steps, and mic preamp gains of
17dB to 47dB in 2dB steps. Gain levels may be modified in
any mode, but may wait for a zero cross detect in the DAC to
eliminate volume control artifacts. This wait for zero cross
may be disabled by setting the ZXD_DISABLE bit (bit 7) in
the VOICETESTCONFIG register to allow immediate
changes.
ANALOG INPUTS AND OUTPUTS
The LM4930 features an analog mono BTL output for con-
nection to an 8Ωexternal speaker. This output can provide
up to 1W of power into an 8Ωload with a 5V analog supply.
LM4930
www.national.com 32
Application Information (Continued)
A single-ended stereo headphone output is also featured,
providing up to 30mW of power per channel into 32Ωwith a
5V analog supply.
A Headphone Sense output is provided on J6 for connection
to an external controller. This pin goes high when a hea-
phone is present (when used as shown in Figure 5) and will
function in all modes independent of other operations the
LM4930 may be currently processing.
The MIC Jack input (J3) provides for a low level analog input.
Pin 3 provides the power to the MIC and the positive input of
the LM4930. Gain for the MIC preamp is set in the GAIN-
CONFIG register.
LM4930
www.national.com33
Physical Dimensions inches (millimeters) unless otherwise noted
36-Bump micro SMD
Order Number LM4930ITL
NS Package Number TLA36KRA
X
1
= 3.230±0.03mm X
2
= 3.408±0.03 X
3
= 0.600±0.075
LM4930
www.national.com 34
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
LLP Package
Order Number LM4930LQ
NS Package Number LQA44A
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
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(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
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www.national.com
LM4930 Audio Subsystem with Stereo Headphone & Mono Speaker Amplifiers
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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